The present invention relates to a method of presenting to the retina of an observer a complete image comprised of a large number of pixels, located along mutually adjacent lines, by deflecting a limited number of pixels shown on a display over the image-perceiving area of the retina of the observer, these pixels consecutively representing all pixels in the image. By image-perceiving area is meant the area of the retina which sees the image display. The invention also relates to an system for use when carrying out the method.
Our Swedish Patent Specification No. 9101778-0 describes a system which can be used to present images with the aid of this principle, among other things. The patent specification describes generally a system for presenting an image on the basis of at least two variables for each pixel, such as pixel position and pixel information. The image is thus comprised of a plurality or pixels, each defined by a pixel position given by two angular coordinates in relation to a reference direction from the observer, and by information relating to each pixel with regard to intensity, color, polarization, etc., at each moment in time.
The novel principle disclosed in the aforesaid patent specification enables the image presentation system, or display, to be divided into two parts, more specifically a first display device located at a distance from the observer, and a second display device located in the field of view between the observer and the first display device. It is also necessary for the presentation system to include means for mutually synchronizing the first and the second display devices.
According to the aforesaid patent specification, when imaging with the aid of two mutually separate display devices, these devices can be provided with different combinations of the three variables X-coordinate, Y-coordinate and pixel information, such as intensity, color, polarization, etc. A total of six combinations are possible for dividing these variables between the two display devices.
Our coterminous Swedish Patent Application No. 9503503-6 describes simplifications to the equipment required with some of these combinations, particularly those combinations in which the display device which is located at a distance from the observer is provided with information relating to the X-coordinate of respective pixels, with or without pixel information. This display device will thus display a line which consecutively shows the pixels in all lines of the image or picture. The line may be oriented in desired directions and be comprised of uniformly illuminated pixels or pixels that contain information relating to intensity, color, polarization, etc. This display can thus be a so-called line display.
The second display is suitably carried by the observer in the form of spectacles (goggles) through which the line display can be viewed, and it is necessary to provide the second display device with means for deflecting the observed or viewed line in the other direction, which is suitably perpendicular to the propagation of the line, so as to obtain a complete image on the retina of the observer. It is thus only on the retina that the image exists in its entirety as a mean value formulation over a maximum time period corresponding to the slowness or integration time of the eye.
The luminance of the obtained image may constitute a limitation of this technique. Another limitation is that when showing only one single line on the display, it is not possible to display directly readable information on this line, i.e. without the assistance of further auxiliaries.
The main object of the present invention is to provide an image displaying method and an image display system in accordance with the aforegoing with which those limitations that are incurred when only one single line is deflected are eliminated, among other things.
The invention is based on the realization that this object can be achieved when instead of deflecting an individual line there are simultaneously deflected a band of lines which lines are generated in parallel on a display such that each of these lines successively represents all lines of an image or of a part-image. The image thus xe2x80x9crollsxe2x80x9d through the band synchronously with deflection of the band in the opposite direction. The band will therewith xe2x80x9cpaintxe2x80x9d the image over the retina of the observer.
Each line in the image will be activated the same number of times as the number of lines included in the band, therewith increasing luminance by a corresponding factor.
Another advantage afforded by the use a band of lines is that certain pixels in the band can be used to present on the display, information that can be read directly by an observer without the assistance of auxiliary means.
Accordingly, a method of the kind defined in the first paragraph is, in accordance with the invention, mainly characterized in that the display shows the pixels in at least one band of a limited number of complete lines in the image; in that the lines in the band are generated in parallel simultaneously, such that each line represents successively the pixels in all lines of the image or of a part-image; and in that the band is deflected as a unit over the image-perceiving area of the retina synchronously with the generation of the lines on the display.
This technique can be used in the construction of simpler display screens, for instance. Thus, the technique enables present-day display screens which correspond to all lines in the image to be limited to a display screen which shows only a few lines and supplement the screen with a pair of spectacles worn by the observer, for instance. This can provide many advantages in those cases where there is insufficient room for a full scale screen.
Remaining features of the aforedefined method and of a system for carrying out the method will be apparent from the following.